Conventional communicating apparatuses that compress data to be transmitted, e.g. image data, and transmit the compressed data to a communication partner are readily available, with facsimile apparatus being one well known example.
In such apparatuses, many different coding methods can be used for compressing the image data. For example, entropy encoding has been frequently used and, recently, variable length coding methods have been developed that are suitable for compressing multivalue image data. Two existing methods are the JPEG and MPEG methods. Digital VTRs, color copy machines, and color facsimiles all use such coding methods, with each type of apparatus using a method whose characteristics are most suited to its purpose.
However, because each type of apparatus operates best with a particular coding method, there can be problems when data encoded according to one method is sent to an apparatus best suited to another method. For example, image data generated by the color image reader of a color copying apparatus may be transmitted through a motion picture image network, e.g., a CATV network, to a digital VTR. In such case, either the encoded data is not easily decoded, or else a characteristic of the encoder in the color image reader has to be adjusted to provide the encoding method used in the digital VTR.
Such an adjustment can be troublesome and complicated, both in its technical aspects and in the burden it may place on the user of the color copying apparatus.